These bio-inspired fibrillar structures reduce viscous drag and turbulence on surfaces of wind turbine blades, the hulls of submarines, and the interior of oil pipelines by up to 40 percent. Reducing drag and turbulence reduces their power consumption by improving machine speed and endurance.
mushroom-shaped fibers — inspired by gecko footpads and lotus leaves — add a controlled, periodic roughness to wind turbine blade, submarine or pipeline surfaces, creating pockets of air
between fibers to produce a slip velocity that reduces viscous drag.
structures are made from a simple micro-molding process and use readily
available, low-cost, commercial materials like silicon rubber and polyurethane plastics.
Any moldable material is compatible with the manufacturing process, allowing
for a wide material selection. This flexibility in materials and easy,
large-scale production make this technology commercially marketable.
In wind tunnel tests, reduced drag by 40 percent and increased lift by 113 percent — the the
highest levels obtained by passive systems used for drag reduction, far surpassing a micro-groove technology called riblets that achieved only a 10 percent reduction in drag.
Fibrillar Structures are Customizable and Tunable for Optimal Performance
The fibrillar structures are made from polymers using photolithography and micro-molding. The fibers can be customized for any surface; the fabrication technique allows control of the diameter, length, cross-sections, and packing of fiber density. It is possible to control the alignment of the stalk and tip separately, which helps create surfaces with anisotropic, or multi-directional, drag properties. Moreover, it is possible to create fiber arrays with heterogeneous fiber geometry, so that individual fibers forming the arrays have varying cross-sectional shape, diameter, and spacing. This tuning ability provides optimal performance for transitional flows.
Wind turbine blades
for the wind energy industry
Submarines or other
underwater bodies, civilian or military
Wing design for the
Pipe flow turbulence
reduction for petroleum industry, water and sewer departments
Turbulence and drag
costs relative to other drag reduction technologies
can be constructed using a wide variety of readily available materials, making
the technology customizable and controlling material costs
with desired fibrillar structures can be manufactured for large-scale applications
like submarines or aeroplanes
Tested highest drag
reduction and lift enhancement of any passive drag reduction system, offering
significant improvement in speed and efficient, reducing power consumption
footprint for military and civilian transportation from improved speed and
reduced power consumption
- Faster, more efficient delivery of materials such as oil, medicine, and troop supplies
About the Researchers
Dr. Luciano Castillo is a Don Kay and Clay Cash Foundation Engineering Chair in Wind Energy and a professor in the Mechanical Engineering department. His areas of expertise are modeling and experimental wind energy array, single−blade aerodynamics for turbine blades, multi−scale and asymptotic methods in turbulent boundary layers, experimental, theoretical, and numerical fluid mechanics, and forced convection heat transfer.
Dr. Burak Aksak is an assistant professor in the Mechanical Engineering department. His research interests include development of bio−inspired devices for adhesion, sensing, actuation and energy harvesting and multi−functional, self−sufficient systems which exploit the increased surface−to−volume ratio and the high sensitivity of micro/nano structures.